I wasn't sure how to title this. My wife has a problem when she uses her phone to check her work voice mail that it stops sending button tones after about 16 or so. When she dials in, she has to enter her phone number so that's 10, then after a few more presses for various options, the phone stops sending out the tones. This is very consistent behavior and has happened when using other automated systems as well. Has anyone else experienced this?